Regulation of Decidualization in Endometrial Stromal Cells by Taurine

Decidualization occurs when endometrial stromal cells are influenced by progesterone. Decidualization promotes the spiral arteries remodeling, endometrial immune tolerance, and the invasion of fetal cells and placental formation—all of which are critical for embryo implantation. In this study, we found that the expression level of SLC6A6, a taurine transporter, increased during decidualization. Stimulation with low concentrations of taurine regulated the decidualization markers—HAND2, FOXO1, PRL, IGFBP1, and IL15 —to a constant level. Low concentrations of taurine induced appropriate decidualization by increasing GSR, which possesses antioxidant properties, thereby reducing the excessive oxidative stress associated with decidualization and suppressing the overreaction of decidualization marker genes caused by oxidative stress. In other words, the presence of taurine in the blood is thought to contribute to successful decidualization, subsequent successful embryo implantation, and maintenance of pregnancy. However, excessive taurine reversed the responses of many genes, including EF1A, which regulates the cell cycle, and its indiscriminate use should be avoided.